Process for making acetic aldehyde



Patented Sept. 29, 1925.

UNITED STATES NEW JERSEY, ASSIGNOR TO THE ROESSLER on NEW YORK, n. Y., A CORPORATION on NEW PROCESS FOR MAKING ACEYIIC ALDEHYDE.

No Drawing. Application filed June 29,

To all w/iom it may concern:

Be it known that I, CARL STUART VVIL- LIAMS, a citizen of the Uni-ted States, and resident of Voodbridge, in the county of Middlesex and State of New Jersey, have invented certain new and useful Improves ments in Processes for Making Acetic Aldehyde, of which the following is a specification. r

This invention relates to new and useful improvements in processes for making acetic aldehyde.

My invention relates in general to the pyrogenetic transformation of ethyl alcohol into acetic aldehyde and in particular to the manufacture of acetic aldehyde from ethyl alcohol by subjecting the ethyl alcohol vapor to the action of heated metallic catalysts, whereby the aldehyde is formed ac- 20 cording to the equation It is known that this reaction proceeds readily in the presence of heated metallic copper; however, the process cannot be operated in a satisfactory manner for more than a short period because the activity of the copper rapidly diminishes to such a point as to preclude the commercial production of acetic aldehyde by this method. I have now discovered that if the copper is first alloyed with zinc I can thereby produce a catalyst having a much greater effective life. The percentage of zinc in the alloy may vary between wide limits. I prefer to use an alloy containing approximately equal parts of copper and zinc, and I have found that commercial brass of good purity of approximately this composition gives good results, but other proportions of zinc and copper may be used within, my invention.

The copper-zinc alloy may be used in a variety of forms, viz as wire, or wire cloth or as granular or globular particles, or as a film deposited upon an inert carrier such as pumice. For reasons of convenience I prefor to use the alloy in a granular form which is known as spelter solder. This is placed in a catalyst chamber of any desired term and maintained at a temperature between -l00 C. and 450 C. I prefer a temperature of approximately 425 C. At

1922. Serial No. 571,796.

lower temperatures the catalyst is relatively inactive and at higher temperatures it deteriorates more rapidly notwithstanding the presence of the zinc.

The products of the reaction consists of a mixture of acetic aldehyde, hydrogen and undecomposed alcohol together with smaller quantities of carbon monoxide, carbon dioxide, methane, etc. This gaseous mixture is cooled and condensed and the acetic aldehyde separated by distillation or other known methods. Undecomposed alcohol is returned to the process as rawjmaterial.

I claim:

1. The process of making acetic aldehyde comprIsing passing the vapor of ethyl alcohol in contact with copper which has been alloyed with a substance to prolong its life; the alloy being maintained at an elevated temperature below that at which it deteriorates rapidly but above that at which it is relatively inactive.

2. The process of making acetic aldehyde comprising passing the vapor of ethyl alcohol in contact with copper which has been alloyed with zinc; the alloy being maintained at a temperature of about 425 C.

3. The process of making acetic aldehyde comprising passing the vapor of ethyl alcohol in contact with copper which has been alloyed with an approximately equal part of zinc, the alloy being mantained at a temperature of about 425 C.

4. The process of making acetic aldehyde comprising passing the vapor of ethyl alcohol in contact with copper which has been alloyed with an approximately equal part of zinc; the alloy being maintained at a temperature between about 400 and 450 C. 5. The process of making acetic aldehyde comprising passing the vapor of ethyl alcohol in contact with copper which has beenalloyed with an approximately equal part of zinc, the alloy being maintained at a temperature between about 400 and 450 C., separating the aldehyde formed and returning to the system the undecomposed alcohol.

Signed at Perth Amboy in the county of Middlesex and State of New Jersey this 28th day of June, A. D. 1922.

CARL STUART WILLIAMS 

